A virtual tape device intervenes between a host device and a tape library device and stores data to be transmitted and received between the host device and the tape library device as a virtual tape volume (logical volume). By storing data on a randomly-accessible medium such as a magnetic disk device as the logical volume in this manner, the virtual tape device carries out tape operations on the magnetic disk device virtually. This allows the virtual tape device to reduce mechanical actions such as tape mounting, loading and unloading to realize high-speed processing.
Japanese Laid-open Patent Publications No. 2004-227127, No. 2003-510679, and No. 2008-77423 disclose related arts.